There has recently been an effort to transform the thermoplastic industry from one that produces plastics that persist in the environment and are made from non-renewable sources, such as oil derived chemicals, to functionally equivalent thermoplastics that can be prepared from renewable resources, such as plant based chemicals, that are biodegradable, having a sufficient yet finite lifetime in the environment. Only two synthetic polymers from renewable feedstocks have exhibited the potential to enter the commodity plastics market: polylactic acid (PLA) and poly-β-hydroxyalkanoate (PHA). Unfortunately, both polymers rely on biotransformations that tend to be expensive even for large scale production. The organic feedstock for PLA is starch or small sugars, which puts the thermoplastic precursor in economic competition with a food source. PHA requires bioengineered plants in a complex process that has yet to demonstrate economic viability.
An attractive alternative is the most abundant organic feedstock cellulose, which is not a human food. Cellulose acetate has been employed commercially as a polymer for more than a century, but requires levels of plasticizers in excess of 30% to be used as an extrudable thermoplastic and as the degree of acetylation decreases, the greater the level of plasticizer that is required. Furthermore, when the degree of acetylation is greater than 2.5, which is common, the cellulose acetate is not biodegradable.
Another way of employing cellulose to provide non-petroleum based polymers is to anaerobically distill it into methanol and develop polymerizable chemicals from methanol. Methanol is the central chemical of one of the few proposed future non-petroleum economies. Presently there are no monomers for biodegradable thermoplastics that are produced from chemicals easily formed from methanol. Hence novel biodegradable thermoplastics that can be derived ultimately from cellulose via a large scale intermediate such as methanol are desirable.